K-Patents PR-03 User Manual
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PR-03 instruction manual
5.10.7 Bench calibration
The calibration of your refractometer system can be checked offline using Standard RI liquids. These are
available at K-Patents with part number PR-2003. The complete set of 10 bottles covers the RI range 1.310-
1.540.
Standard RI liquids are also available directly from: Cargille Laboratories, 55 Commerce Road, Cedar
Grove, New Jersey 07009, USA. WWW: http://www.cargille.com/, e-mail: [email protected], phone:
973-239-6633, fax: 973-239-6096.
The bench calibration should be done at room temperature, but the temperature does not have to be exactly
25
◦
C as the displayed value is temperature compensated. If the sensor is hot, let it cool down to ambient
temperature.
Use a sample holder, Figure 5.15 and "strip" the sensor, i.e. use PR-03-M sensor without the flow cell and
PR-03-W sensor without the valve body. Sample holders are available at K-Patents with part number PR-
1010 for Sanitary refractometer PR-03-A, PR-1012 for Probe refractometer PR-03-P and Compact process
refractometer PR-03-D.
Figure 5.15
Sample holder PR-1010
Use the same three R.I. liquids that were used for the Delivery Data Sheet of this sensor. See Appendices B,
“Information about Delivery data sheet (DDS)”, and D, “Instrument verification ISO 9000”, for more
information.
Just a few drops of sample are enough for reliable measurement. However, the sample must be covered to
prevent outside light to reach the prism. Sample leakage from holder may give measurement error. Always
use repeated measurements for each sample.
Note:
Clean the prism and the sample holder well with alcohol
between the different R.I. samples.
Important:
Dispose of used RI liquids. Never put liquids back into the bottle after use!
Important:
Offline calibration using process liquid very seldom gives reliable results, problems are caused
by
− low flow which makes sample to form an unrepresentative film on the prism
− sample evaporation at high temperature or undissolved solids at low temperature giving devia-
tions from laboratory determinations
− an ageing sample which is not representative
− outside light reaching the prism
Thus calibration using the process liquid should always be made inline, see Section 5.10.6, “Field calibra-
tion”.